A process for the production of spice extracts by extraction in two stages with a non-toxic gas as solvent is known from German Pat. No. 2,127,611. According to the procedure disclosed, essential oils acting as aroma components are removed by extraction with dry gas and subsequently the portions acting as flavor carriers are extracted with a gas containing water vapor, which extractions are supercritical with regard to temperature and pressure. This known process has many disadvantageous aspects by which the quality of the spice extracts can be negatively influenced. Since this process works in the supercritical temperature range in both stages, the highly temperature-sensitive essential oils are subjected in the first stage to a high thermal stress. Furthermore, water is added in the extraction in the second stage, which addition can result in undesired quality losses by the reaction of the spice ingredients with the added water. Also, the introduction of the water requires the opening of the closed extraction system, so that the sensitive ingredients can also come in contact with atmospheric oxygen. The extraction of the essential oils in the first stage, if it is to be substantially quantitative, takes a long time, which means that the products are exposed to the higher temperature for an excessively long time.
It is also known to effect extractions with liquid carbon dioxide, where both the pressure and the temperature are in the subcritical range. However, in this process for the extraction of spices, the results obtained are highly unsatisfactory because the yields of ingredients are low and high residual values remain in the extraction residue.
The problem was therefore to find an extraction method which permits the extraction of essential oils acting as aroma components, which oils are particularly sensitive to high temperatures, in a virtually quantitative amount in a minimum of time under mild temperature conditions, that is, to achieve fractioning of the aroma components from the flavor carriers in a simple manner. Furthermore, it should be possible to extract the flavor carriers in the same closed system without the addition of water to exclude all the unfavorable effects resulting from the addition of water.